Amoxicillin: Uses, precautions & interactions!

Amoxicillin is a Beta-lactam antibiotic, of the subtype penicillin drugs, used to treat various bacterial infections.


  • Middle ear infection
  • Pharyngitis
  • Laryngitis
  • Sinusitis
  • Chlamydia
  • Urinary tract infection
  • Bacterial skin infection
  • Lower respiratory tract infection
  • Infection of H.Pyroli
  • Lyme Disease


Dosage forms available:

  • Tablet: 500 mg, 875 mg
  • Chewable tablet: 125 mg, 200 mg
  • Capsule: 250 mg, 500 mg
  • Powder for suspension: 125 mg/5 ml, 200 mg/5 ml, 250 mg/5 ml, 400 mg/5 ml
  • Injection
  • Amoxicillin + clavulanic acid: 625 mg, 1000 mg

Dosage guidelines: 

  • H.Pyroli infection: 1 g every 8 hours for 14 days.
  • Lyme disease: 500 mg tablet/capsule three times a day for 14 days.
  • Sinusitis: 500 mg tablet/capsule every 12 hours for 5-7 days.

Missed dose: Take the missed dose as soon as you remember. Skip the missed dose if it is almost time for your next scheduled dose. Do not take extra medicine to make up the missed dose.

a) Gastric lavage and induction of vomiting
b) Dialysis & hydration therapy.


  • Abdominal cramps
  • Back pain
  • Bleeding gums
  • Chest pain
  • Chills
  • Diarrhea
  • Nausea & vomiting
  • Rash & inflammation
  • Loss of appetite
  • Weight loss
  • Sore throat
  • Pale skin
  • Muscle ache


  • Severe allergic reaction in people with allergy to penicillin drugs.
  • Superinfection
  • Candidiasis
  • Colitis
  • Inflammation of the veins
  • Dermatitis
  • Urticaria
  • Elevated liver enzymes
  • Cholecystitis
  • Jaundice
  • Mild hepatitis
  • Crytalluria
  • Anemia
  • Convulsion
  • Tooth discoloration


Amoxicillin is contraindicated and precaution is advised in patients with following conditions:

  • Allergy to penicillin type of antibiotics.
  • Mononucleosis
  • Phenylketonuria
  • Renal impairment
  • Hepatic impairment
  • Immune disorders
  • Nutritional deficiency
  • Altered bacterial flora & fauna in the intestines
  • Diabetes
  • Hemodialysis


  • Probenecid may increase the concentration & residence time of amoxicillin.
  • Allopurinol may increase the potential for allergic reactions to amoxicillin.
  • Penicillins can increase the serum concentration of methotrexate.
  • Tetracyclines when given in presence of amoxicillin, reduce the therapeutic effect of the latter.
  • The drug when given with oral contraceptives may reduce the absorption of estrogen, due to altered intestinal flora.
  • Other antibacterials like chloramphenicol, sulphonamides, macrolides, etc can interfere with the antibiotic property of amoxicillin.
  • Amoxicillin can increase the anticoagulant effect of anticoagulant drugs & Vitamin K, when given concomitantly.


  • Pregnancy: The drug is a category B drug and is considered safe for use, causing no harm to the fetus.
  • Breast feeding: The drug gets excreted in the milk & therefore precaution is advised.
  • Children: No specific data is available, although combination dose of Amoxicillin & clavulanic acid is given to children for specific bacterial infections.